I click on those "you've won a free w/e" things all the time, except you have to enter a credit card number in usually and complete hard offers. And now I get like, 4,000 emails everyday from those.
Ways to annoy people:
Arrive at a meeting late, say you're sorry, but you didn't have time for lunch, and you're going to be nibbling during the meeting. Then eat raw potatoes.
Ask people what gender they are,or
Disagree strongly with everything anybody says:)